Antenna bandwidth enhancement for an electronic device

ABSTRACT

Techniques are disclosed for configuring a broadband antenna system. An example electronic device includes a first antenna operating at a first frequency range and coupled to a first transceiver via a first signal path comprising a first indirect feed. The electronic device also includes a second antenna operating at a second frequency range and coupled to a second transceiver via a second signal path comprising a second indirect feed, wherein the first frequency range is lower than the first frequency range. The electronic device also includes a third antenna operating at the second frequency range and coupled to a third transceiver via a second signal path comprising a third indirect feed. Additionally, the first antenna is coupled to the first antenna and the second antenna by a capacitive coupling element.

TECHNICAL FIELD

This disclosure relates generally to portable and mobile computingdevices such as laptop computers, tablet computers, smart phones, andthe like. More specifically, the disclosure describes techniques forimproving antenna bandwidth in such devices.

BACKGROUND

The industrial design of handheld wireless devices will often have ahigh priority in the overall design process, and full metal bodies areoften used for high-end phones to get an appealing industrial design.These types of phones will only have limited space for the antennas inthe top and the bottom of the device, making it difficult to design anantenna system with broad bandwidth. Thus, devices such as smart phonesare often equipped with narrow-banded tunable antennas where only one ora limited number of adjacent frequency bands are covered at any giventime.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an exemplary electronic device such as asmart phone or tablet PC.

FIG. 2 is a front view of the antenna system of FIG. 1 with the antennawindow removed to show additional details.

FIG. 3 is a circuit diagram of the antenna system shown in FIGS. 1 and2.

FIG. 4 is a graph illustrating simulated impedance characteristics forthe low frequency antenna shown in FIGS. 1 and 2.

FIG. 5 is a graph illustrating simulated impedance characteristics forthe first high frequency antenna shown in FIGS. 1 and 2.

FIG. 6 is a graph illustrating simulated impedance characteristics forthe second high frequency antenna shown in FIGS. 1 and 2.

FIG. 7 is a graph illustrating simulated isolation levels between thetwo high frequency antennas shown in FIG. 7.

FIG. 8 is another embodiment of an antenna system in accordance withembodiments of the present techniques.

FIG. 9 is a circuit diagram of the antenna system shown in FIG. 8.

FIG. 10 is a graph illustrating simulated impedance characteristics forthe first high frequency antenna shown in FIGS. 8 and 9.

FIG. 11 is a graph illustrating simulated impedance characteristics forthe second high frequency antenna shown in FIGS. 8 and 9.

FIG. 12 is a graph illustrating simulated isolation levels between thetwo high frequency antennas shown in FIGS. 8 and 9.

FIG. 13 is a block diagram of an electronic device with a multiple highbandwidth antenna systems.

FIG. 14 is a process flow diagram of an example method of operating anelectronic device with multiple high bandwidth antenna systems.

The same numbers are used throughout the disclosure and the figures toreference like components and features. Numbers in the 100 series referto features originally found in FIG. 1; numbers in the 200 series referto features originally found in FIG. 2; and so on.

DETAILED DESCRIPTION

The subject matter disclosed herein relates to techniques for improvingor enhancing the bandwidth of antennas or antenna arrays in an antennasystem. There are multiple technologies in which broad antenna bandwidthis desirable for improved performance. For example, the 3rd GenerationPartnership Project (3GPP) Long Term Evolution (LTE)-Advancedspecification provides carrier aggregation, which allows mobile networkoperators to combine a number of separate LTE carriers to increase userdata rates and network capacity. Carrier aggregation can be combinedwith other techniques such as Quadruple Best Antenna Selection (QBAS)and 4×4 Multiple-Input Multiple-Output (MIMO).

To implement carrier aggregation, the antenna system will sometimes beexpected to cover multiple non-adjacent LTE bands, such as the bandsreferred to herein as LB (699 MHz to 960 MHz), MB (1710 MHz to 2170MHz), HB (2300 MHz to 2690 MHz), UB (3400 MHz to 3800 MHz), and XB (5150MHz to 5850 MHz). Four full bandwidth antennas all covering MB, HB, UBand XB frequency bands will be used to combine QBAS and 4×4 MIMO withall carrier aggregation combinations. This will typically require alarge volume, when using traditional antenna designs, which is in directconflict with the industrial design of the device. Even if a largevolume was allocated, it would still be difficult to achieve goodisolation between the wide-banded high frequency antennas.

The present disclosure describes an antenna system that provides anumber of wide-band antennas that are able to fit within a small formfactor such as a smart phone or tablet PC. The techniques describedherein may be useful for implementing LTE-Advanced carrier aggregationin combination with QBAS and 4×4 MINO. Accordingly, the presentdescription makes reference to the LTE frequency bands. However, it willbe appreciated that the present techniques may also be used in otherwireless communication standards.

FIG. 1 is a perspective view of an electronic device such as a smartphone or tablet PC. The electronic device 100 includes an outer shell102, the dimensions of which may be primarily determined based onaesthetic considerations, such as the screen size, weight, and others.As an example, the outer shell 102 may have dimensions of 90 millimeters(mm) wide by 190 mm tall by 9.5 mm thick. However, other form factordimensions may be possible, for example, for smaller smart phones orlarger laptops or tablet PCs. The outer shell may be metal.

The outer shell 102 of the device also includes an antenna window 104which provides an area in and around which antennas can be disposed. Theantenna window 104 may be formed of in-molded plastic or other materialthat is transparent to electromagnetic waves. As shown in FIG. 1, theantenna window 104 may extend the full width of the electronic device100 and may extend upward by about 15 mm. Other dimensions are alsopossible.

The electronic device 100 includes a low frequency antenna 106 and twohigh frequency antennas 108 and 110, all of which are disposed aroundthe outside of the antenna window 104. The two high frequency antennas108 and 110 are flat metal bars that wrap around respective corners ofthe electronic device 100. The low frequency antenna 106 is a flat metalbar that forms the bottom surface of the electronic device 100. Theantennas 106, 108 and 110 are separated from one another and from theouter shell 102 by gaps 112. The material that forms the antenna window104 may fill the gaps 112 to maintain the separation. The width of eachgap 112 may be approximately 1 mm. In some examples, the low frequencyantenna 106 may have an opening 114 suitable for disposing a connector,for example. The connector may be used for coupling the electronicdevice 100 to a power source and/or other electronic devices.

In some examples, the low frequency antenna 106 is configured to operateat 699 MHz to 960 MHz, and the high frequency antennas 108 and 110 areconfigured to operate at the MB and HB frequency bands spanning from1710 MHz to 2690 MHz. Other frequency ranges are possible.

It will be appreciated the antenna systems shown in the presentdisclosure can be duplicated at the top end of the electronic device100. For example, the electronic device 100 may also include anotherantenna window at the top end of the electronic device 100, which mayinclude additional antennas arranged in the mirror image of the antennasat the bottom side of the electronic device 100. Additional features ofthe antennas are shown in FIGS. 2 and 3.

FIG. 2 is a front view of the antenna system of FIG. 1 with the antennawindow removed to show additional details. As shown in FIG. 2, theantenna system components may be disposed on a supporting substrate 200such as a Printed Circuit Board (PCB). The substrate 200 can alsoinclude electrical connections from the one or more communicationssubsystems to the antennas. The low frequency antenna 106 is coupled toground through a grounding element 202, and coupled to a low frequencytransceiver 204 through an indirect feed element 206. The indirect feedelements shown in FIG. 2 are capacitive feed elements. However, in someembodiments, the indirect feed elements may be inductive feed elements.

The first high frequency antenna 108 is coupled to ground through agrounding element 208. The first high frequency antenna 108 is alsocoupled to a first high frequency transceiver 210 through an indirectfeed element 212. Similarly, the second high frequency antenna 110 iscoupled to ground through a grounding element 214, and to a second highfrequency transceiver 216 through an indirect feed element 218. Thegrounding elements 202, 208 and 214 may couple the respective antenna toground directly or may couple the respective antenna to ground through apassive circuit element such as an inductor. Each transceiver may be acircuit module mounted on the circuit board that provides integratedtransmission and reception capabilities. However, the term transceiveras used herein more broadly refers to a circuit module that can providereception capability, or transmission capability, or both.

The antenna system also includes a pair of coupling capacitors 220 thatcouple the high frequency antennas 108 and 110 to the low frequencyantenna 106. This enables the low frequency antenna to operate in adual-loop mode, wherein the path of the current is through the lowfrequency antenna 106 and both high frequency antennas 108 and 110.Thus, the two high frequency antennas are a part of the resonantstructure by which the low frequency transmissions are radiated. Each ofthe two high frequency antennas 108 and 110 operate in a monopole mode.

In some examples, the low frequency antenna 106 is configured to coverthe low band frequencies in two switch stages. For example, the firstswitch stage may cover a frequency range of 699 to 790 MHz while thesecond switch stage may cover a frequency range of 791 to 960 MHz. Thetwo switch stages may be selected by controlling the capacitance valuesof the capacitors 220 to change the resonance of the low frequencyantenna 106 (including antenna elements 108 and 110).

The two capacitors 220 may be positioned at a points on the antennaelements where the currents for the full high frequency range is verylow. This means that the resonances for the low frequency range can betuned by changing the capacitor values without significantly affectingthe currents for the two individual high frequency monopole modes,whereby the high frequency resonances are independent of the lowfrequency range resonances.

FIG. 3 is a circuit diagram of the antenna system shown in FIGS. 1 and2. As shown in FIG. 3, the low frequency antenna 106 is coupled to thelow frequency transceiver 204 through the indirect feed element 206,high frequency antenna 108 is coupled to the first high frequencytransceiver 210 through the indirect feed element 212, and highfrequency antenna 110 is coupled to the second high frequencytransceiver 216 through the indirect feed element 218. The highfrequency antennas 108 and 110 are coupled to ground through resonanceinductors 302. The resonance inductors 302 are configured to tune theresonant frequency of the high frequency antennas 108 and 110 and mayhave an inductance value in the range of 1.4 nanoHenry (nH) to around 10nH.

The feed path for the high frequency antennas 108 and 110 also includediscrete inductors 304 and delay lines 306. The discrete inductors 304impedance match the output of the transceivers 210 and 216 to theantennas 108 and 110 and may have inductance values in the range of 2 nHto about 20 nH. The delay lines 306 are used to shift the phase into thecorrect position on the Smith Chart for the discrete inductors 304 toimprove the impedance match of the antenna. For example, the delay lines306 and discrete inductors 304 may provide an impedance match resultingin a return loss of about −6 dB.

Additionally, the low frequency antenna 106 is coupled to the highfrequency antennas 108 and 110 through capacitors 220. As mentionedabove, the capacitors 220 may be adjustable to implement the two switchstages of the low frequency antenna 106. Accordingly, the capacitors 220may be coupled to an antenna system controller 308 configured to varythe capacitance of the capacitors 220.

The antenna system may also include an impedance tuner 310 at the outputof the low frequency transceiver 204. The impedance tuner 310 isconfigured to impedance match the low frequency transceiver 204 to thelow frequency antenna 106. The impedance tuner 310 may be coupled to theantenna system controller 308 and configured to tune the impedance inresponse to the changes in the switch stage selection.

FIGS. 4-7 illustrate some of the electrical characteristics of theantenna system shown in FIGS. 1 and 2. FIG. 4 is a graph illustratingsimulated impedance characteristics for the low frequency antenna shownin FIGS. 1 and 2. The vertical axis represents the reflectioncoefficient, S11, in Log magnitude as seen at the low frequencytransceiver 204 (FIG. 2). The graph illustrates that the frequency bandof 699 MHz to 960 MHz is covered in two switch stages. The first switchstage is represented by line 402, and the second switch stage isrepresented by line 404. By using two switch stages, a reflectioncoefficient of less than −6 decibels (dB) can be achieved across theentire low frequency band.

FIG. 5 is a graph illustrating simulated impedance characteristics forthe first high frequency antenna shown in FIGS. 1 and 2. In thisembodiment, the first high frequency antenna is configured to operate atthe MB and HB frequency bands spanning from 1710 MHz to 2690 MHz. Asshown in FIG. 5, a reflection coefficient of less than −6 decibels (dB)can be achieved across the both frequency bands.

FIG. 6 is a graph illustrating simulated impedance characteristics forthe second high frequency antenna shown in FIGS. 1 and 2. In thisembodiment, the second high frequency antenna is configured to operateat the MB and HB frequency bands spanning from 1710 MHz to 2690 MHz. Asshown in FIG. 6, a reflection coefficient of less than −6 decibels (dB)can be achieved across both frequency bands.

FIG. 7 is a graph illustrating simulated isolation levels between thetwo high frequency antennas shown in FIG. 7. Specifically, the graph ofFIG. 7 shows the log magnitude signal level, S21, received at one highfrequency antenna from the other high frequency antenna. FIG. 7demonstrates that a suitable isolation level of greater than −15 dB canbe achieved across the entire frequency band of the high frequencyantennas.

FIG. 8 is another embodiment of an antenna system in accordance withembodiments of the present techniques. In the embodiment shown in FIG.8, the low frequency antenna 106 operates as described in relation toFIG. 2. The high frequency antennas include the antenna elements 108 and110 which are configured to resonate at the MB and HB frequency bands asdescribed in relation to FIG. 2. In addition, the two high frequencyantennas include additional antenna elements configured to resonate atthe UB and XB frequency bands. The XB antenna elements 802 and 806 areconfigured to resonate at the UB frequency band (5150 to 5850 MHz), andthe UB antenna elements 804 and 808 are configured to resonate at the XBfrequency band (3400 to 3800 MHz). The high frequency antenna elements108 and 802 are fed by the indirect feed element 810, and the highfrequency antenna elements 110 and 806 are fed by the indirect feedelement 812. Antennas elements 804 and 808 are parasitic elements thatare driven by antenna elements 802 and 806 respectively.

FIG. 9 is a circuit diagram of the antenna system shown in FIG. 8. Inthis embodiment, the circuit includes the low frequency antenna 106, thehigh frequency antenna elements 108 and 110, and the various circuitcomponents related to the operation of those antennas, which weredescribed above in relation to FIG. 3.

In addition, the XB antenna element 802 is coupled to the first highfrequency transceiver 210 through the discrete inductor 304, anadditional delay line 902, and an indirect feed 914. The high frequencyantenna element 108 is coupled to the first high frequency transceiver210 through the discrete inductor 304, delay line 306, and an indirectfeed 916. The indirect feeds 914 and 916 correspond with the indirectfeed element 810 shown in FIG. 8. The XB antenna element 802 is coupledto ground through an additional resonant inductor 922. The UB antennaelement 804 is in this embodiment is coupled directly to ground butcould also be coupled to ground via a resonance inductor and is drivenby the XB antenna element 802. Similarly, the XB antenna element 806 iscoupled to the second high frequency transceiver 216 through thediscrete inductor 304, an additional delay line 902, and an indirectfeed 918. The XB antenna element 806 is coupled to ground through anadditional resonant inductor 922. The high frequency antenna element 110is coupled to the first high frequency transceiver 210 through thediscrete inductor 304, delay line 306, and an indirect feed 920. Theindirect feeds 918 and 920 correspond with the indirect feed element 812shown in FIG. 8. The UB antenna element 808 is, in this embodiment,coupled directly to ground but could also be coupled to ground via aresonance inductor and is driven by the XB antenna element 806.

FIGS. 10-12 illustrate some of the electrical characteristics of theantenna system shown in FIGS. 8 and 9. In this embodiment, the impedancecharacteristics of the low frequency antenna are substantially the sameas shown in FIG. 4, indicating that the additional high frequencyantenna elements 802, 804, 806, and 808 have little impact on theperformance of the low frequency antenna.

FIG. 10 is a graph illustrating simulated impedance characteristics forthe first high frequency antenna shown in FIGS. 8 and 9. In thisembodiment, the first high frequency antenna is configured to operate atthe MB, HB, UB, and XB frequency bands spanning from 1710 MHz to 5850MHz. As shown in FIG. 10, a reflection coefficient of less than −6decibels (dB) can be achieved across the most of the LTE frequency bandsand the 5.6 GHz WLAN frequency band.

FIG. 11 is a graph illustrating simulated impedance characteristics forthe second high frequency antenna shown in FIGS. 8 and 9. In thisembodiment, the second high frequency antenna is configured to operateat the MB, HB, XB, and UB frequency bands spanning from 1710 MHz to 5850MHz. As shown in FIG. 10, a reflection coefficient of less than −6decibels (dB) can be achieved across the all of the LTE frequency bandsand the 5.6 GHz WLAN frequency band.

FIG. 12 is a graph illustrating simulated isolation levels between thetwo high frequency antennas shown in FIGS. 8 and 9. Specifically, thegraph of FIG. 12 shows the log magnitude signal level, S21, received atone high frequency antenna from the other high frequency antenna. FIG.12 demonstrates that a suitable isolation level of greater than −14 dBcan be achieved across the entire frequency band of the high frequencyantennas.

FIG. 13 is a block diagram of an electronic device with a multiple highbandwidth antenna systems. The electronic device 1300 may be, forexample, a tablet computer, mobile phone, smart phone, or a smart watch,among others. The electronic device 1300 may include a centralprocessing unit (CPU) 1302 that is configured to execute storedinstructions, as well as a memory device 1304 that stores instructionsthat are executable by the CPU 1302. The CPU may be coupled to thememory device 1304 by a bus 1306. Additionally, the CPU 1302 can be asingle core processor, a multi-core processor, a computing cluster, orany number of other configurations. Furthermore, the electronic device1300 may include more than one CPU 1302. The memory device 1304 caninclude random access memory (RAM), read only memory (ROM), flashmemory, or any other suitable memory systems. For example, the memorydevice 1304 may include dynamic random access memory (DRAM).

The electronic device 1300 may also include a graphics processing unit(GPU) 1308. As shown, the CPU 1302 may be coupled through the bus 1306to the GPU 1308. The GPU 1308 may be configured to perform any number ofgraphics operations within the electronic device 1300. For example, theGPU 1308 may be configured to render or manipulate graphics images,graphics frames, videos, or the like, to be displayed to a user of theelectronic device 1300.

The electronic device 1300 can also include a storage device 1310. Thestorage device 1310 is a non-volatile physical memory such as a harddrive, an optical drive, a flash drive, an array of drives, or anycombinations thereof. The storage device 1310 can store user data, suchas audio files, video files, audio/video files, and picture files, amongothers. The storage device 1310 can also store programming code such asdevice drivers, software applications, operating systems, and the like.The programming code stored to the storage device 1310 may be executedby the CPU 1302, GPU 1308, or any other processors that may be includedin the electronic device 1300.

The electronic device 1300 can also include a display 1312 and one ormore user input devices 1314, such as switches, buttons, a keyboard, amouse, or trackball, among others. One of the input devices 1314 may bea touchscreen, which may be integrated with the display 1312.

The electronic device 1300 also includes transceivers 1316 and feedsystem 1318. The transceivers 1316 may be any of the low frequency andhigh frequency transceivers described above in FIGS. 3 and 9. Similarly,the feed systems 1318 may be any of the feed systems described above inrelation to FIGS. 3 and 9.

The programming code stored to the storage device 1310 may include theantenna system controller 308. As described above, the antenna systemcontroller 308 may be configured to control the impedance tuner 310(FIGS. 3 and 9) to tune the low frequency antenna in response tochanging conditions. The antenna system controller 308 may also beconfigured to select a switch stage for the low frequency antenna bysending a tuning signal to the capacitors 220 (FIGS. 3 and 9). In someexamples, rather than being implemented as programming code stored tothe storage device 1310, the antenna system controller 308 may beimplemented as firmware or logic circuits included in one or morededicated processors such as an Application Specific Integrated Circuit(ASIC), a Field Programmable Gate Array (FPGA), a System on a Chip(SOC), and combinations thereof.

The block diagram of FIG. 13 is not intended to indicate that theelectronic device 1300 is to include all of the components shown in FIG.13. Rather, the electronic device 1300 can include fewer or additionalcomponents not shown in FIG. 13, depending on the details of thespecific implementation. Furthermore, any of the functionalities of theCPU 1302, or the GPU 1308 may be partially, or entirely, implemented inhardware and/or in a processor. For example, the functionality may beimplemented in any combination of Application Specific IntegratedCircuits (ASICs), Field Programmable Gate Arrays (FPGAs), logiccircuits, and the like.

FIG. 14 is a process flow diagram of an example method of operating anelectronic device with multiple high bandwidth antenna systems. Themethod 1400 may be performed by the electronic device 1300 andimplemented by circuitry included in the transceivers 1316, the feedsystem 1318, and the antenna system controller 308. The circuitry may beembodied in hardware, such as logic circuitry or one or more processorsconfigured to execute instructions stored in a non-transitory,computer-readable medium.

At block 1402, a low frequency antenna is through a first signal pathwith a first indirect feed. At block 1404, a first high frequencyantenna is fed through a second signal path with a second indirect feed.At block 1406, a second high frequency antenna is fed through a thirdsignal path with a third indirect feed. The first antenna may be coupledto the second antenna and the third antenna through capacitive couplingelements.

The method 1400 should not be interpreted as meaning that the blocks arenecessarily performed in the order shown. Furthermore, fewer or greateractions can be included in the method 1400 depending on the designconsiderations of a particular implementation.

EXAMPLES

Example 1 is an electronic device with a broadband antenna system. Theelectronic device includes a first antenna to operate at a firstfrequency range and coupled to a first transceiver through a firstsignal path including a first indirect feed. The electronic device alsoincludes a second antenna to operate at a second frequency range andcoupled to a second transceiver through a second signal path including asecond indirect feed, wherein the first frequency range is lower thanthe second frequency range. The electronic device also includes a thirdantenna to operate at the second frequency range and coupled to a thirdtransceiver through a third signal path including a third indirect feed.The first antenna is coupled to the second antenna and the third antennathrough capacitive coupling elements.

Example 2 includes the electronic device of example 1, including orexcluding optional features. In this example, the first antenna is tooperate in a dual loop mode through the second antenna and the thirdantenna.

Example 3 includes the electronic device of any one of examples 1 to 2,including or excluding optional features. In this example, thecapacitive coupling elements are tunable to adjust a resonant frequencyof the first antenna.

Example 4 includes the electronic device of any one of examples 1 to 3,including or excluding optional features. In this example, the firstfrequency range of the first antenna is covered in two switch stages,which are selectable by adjustment of the capacitive coupling elements.

Example 5 includes the electronic device of any one of examples 1 to 4,including or excluding optional features. In this example, the firstfrequency range of the first antenna is between 699 MHz and 960 MHz.

Example 6 includes the electronic device of any one of examples 1 to 5,including or excluding optional features. In this example, the secondantenna includes a single resonant element configured to resonate at afrequency range between 1710 MHz and 2690 MHz.

Example 7 includes the electronic device of any one of examples 1 to 6,including or excluding optional features. In this example, the secondantenna includes a first element configured to resonate at a frequencyrange between 1710 MHz and 2690 MHz, and a second element configured toresonate at a frequency range between 3400 and 3800 MHz.

Example 8 includes the electronic device of any one of examples 1 to 7,including or excluding optional features. In this example, the secondantenna includes: a first element configured to resonate at a frequencyrange between 1710 MHz to 2690 MHz; a second element configured toresonate at a frequency range between 3400 and 3800 MHz; and a thirdelement configured to resonate at a frequency range between 5150 and5850 MHz. Optionally, the first element and second elements are coupledto an indirect feed, and the third element is fed by the second element.

Example 9 includes the electronic device of any one of examples 1 to 8,including or excluding optional features. In this example, the firstantenna includes a straight metal bar disposed along a first surface ofthe electronic device; the second antenna includes a first curved metalbar disposed around a first corner of the electronic device adjacent tothe first surface; and the third antenna includes a second curved metalbar disposed around a second corner of the electronic device adjacent tothe first surface.

Example 10 is a method of operating an electronic device with abroadband antenna system. The method includes feeding a first antenna ata first frequency range through a first signal path including a firstindirect feed; feeding a second antenna at a second frequency rangethrough a second signal path including a second indirect feed, whereinthe first frequency range is lower than the second frequency range; andfeeding a third antenna at the second frequency range through a thirdsignal path including a third indirect feed. The first antenna iscoupled to the second antenna and the third antenna through capacitivecoupling elements.

Example 11 includes the method of example 10, including or excludingoptional features. In this example, the first antenna operates in a dualloop mode through the second antenna and the third antenna.

Example 12 includes the method of any one of examples 10 to 11,including or excluding optional features. In this example, the methodincludes adjusting a capacitance of the capacitive coupling elements toadjust a resonant frequency of the first antenna.

Example 13 includes the method of any one of examples 10 to 12,including or excluding optional features. In this example, the methodincludes selecting a first switch stage of the first antenna byselecting a first capacitance level of the capacitive coupling elements;and selecting a second switch stage of the first antenna by selecting asecond capacitance level of the capacitive coupling elements.

Example 14 includes the method of any one of examples 10 to 13,including or excluding optional features. In this example, the firstfrequency range of the first antenna is between 699 MHz to 960 MHz.

Example 15 includes the method of any one of examples 10 to 14,including or excluding optional features. In this example, the secondantenna includes a single resonant element configured to resonate at afrequency range between 1710 MHz and 2690 MHz.

Example 16 includes the method of any one of examples 10 to 15,including or excluding optional features. In this example, the secondantenna includes a first element configured to resonate at a frequencyrange between 1710 MHz and 2690 MHz, and a second element configured toresonate at a frequency range between 3400 and 3800 MHz.

Example 17 includes the method of any one of examples 10 to 16,including or excluding optional features. In this example, the secondantenna includes: a first element configured to resonate at a frequencyrange between 1710 MHz to 2690 MHz; a second element configured toresonate at a frequency range between 3400 and 3800 MHz; and a thirdelement configured to resonate at a frequency range between 5150 and5850 MHz. Optionally, the method includes feeding the first element andsecond element through the second indirect feed, and feeding the thirdelement through the second element.

Example 18 includes the method of any one of examples 10 to 17,including or excluding optional features. In this example, the firstantenna includes a straight metal bar disposed along a first surface ofthe electronic device. Additionally, the second antenna includes a firstcurved metal bar disposed around a first corner of the electronic deviceadjacent to the first surface. Furthermore, the third antenna includes asecond curved metal bar disposed around a second corner of theelectronic device adjacent to the first surface.

Example 19 is an electronic device with a broadband antenna system. Theelectronic device includes a first antenna including a straight metalbar disposed along a first surface of the electronic device and coupledto a first transceiver through a first indirect feed. The electronicdevice also includes a second antenna including a first curved metal bardisposed around a first corner of the electronic device adjacent to thefirst surface and coupled to a second transceiver through a secondindirect feed. The electronic device also includes a third antennaincluding a second curved metal bar disposed around a second corner ofthe electronic device adjacent to the first surface and coupled to athird transceiver through a third indirect feed.

Example 20 includes the electronic device of example 19, including orexcluding optional features. In this example, the first antenna is tooperate at a first frequency range, and the second antenna and thirdantenna are to operate at a second frequency range higher than the firstfrequency range.

Example 21 includes the electronic device of any one of examples 19 to20, including or excluding optional features. In this example, the firstantenna operates in a dual loop mode through the second antenna and thethird antenna.

Example 22 includes the electronic device of any one of examples 19 to21, including or excluding optional features. In this example, theelectronic device includes a first capacitive element coupling thestraight metal bar of the first antenna to the first curved metal bar ofthe second antenna, and a second capacitive element coupling thestraight metal bar of the first antenna to the second curved metal barof the third antenna. Optionally, the first capacitive element and thesecond capacitive element are tunable to adjust a resonant frequency ofthe first antenna. Optionally, a first frequency range of the firstantenna is covered in two switch stages, which are selectable byadjustment of the first capacitive element and the second capacitiveelement.

Example 23 includes the electronic device of any one of examples 19 to22, including or excluding optional features. In this example, a firstfrequency range of the first antenna is between 699 MHz to 960 MHz.

Example 24 includes the electronic device of any one of examples 19 to23, including or excluding optional features. In this example, thesecond antenna includes a first element configured to resonate at afrequency range between 1710 MHz and 2690 MHz, and a second elementconfigured to resonate at a frequency range between 3400 and 3800 MHz.

Example 25 includes the electronic device of any one of examples 19 to24, including or excluding optional features. In this example, thesecond antenna includes: a first element configured to resonate at afrequency range between 1710 MHz to 2690 MHz; a second elementconfigured to resonate at a frequency range between 3400 and 3800 MHz;and a third element configured to resonate at a frequency range between5150 and 5850 MHz. Optionally, the first element and second element arecoupled to an indirect feed, and the third element is fed by the secondelement.

Example 26 is a method of manufacturing an electronic device with abroadband antenna system. The method includes disposing a first antennaincluding a straight metal bar along a top surface of the electronicdevice; disposing a second antenna including a first curved metal bararound a first corner of the electronic device adjacent to the topsurface; disposing a third antenna including a second curved metal bararound a second corner of the electronic device adjacent to the firstsurface; coupling the first antenna to a first transceiver through afirst indirect feed; coupling the second antenna to a second transceiverthrough a second indirect feed; and coupling the third antenna to athird transceiver through a third indirect feed.

Example 27 includes the method of example 26, including or excludingoptional features. In this example, the first antenna is to operate at afirst frequency range, and the second antenna and third antenna are tooperate at a second frequency range higher than the first frequencyrange.

Example 28 includes the method of any one of examples 26 to 27,including or excluding optional features. In this example, the firstantenna operates in a dual loop mode through the second antenna and thethird antenna.

Example 29 includes the method of any one of examples 26 to 28,including or excluding optional features. In this example, the methodincludes coupling the straight metal bar of the first antenna to thefirst curved metal bar of the second antenna through a first capacitiveelement; and coupling the straight metal bar of the first antenna to thesecond curved metal bar of the third antenna through a second capacitiveelement. Optionally, the first capacitive element and the secondcapacitive element are tunable to adjust a resonant frequency of thefirst antenna. Optionally, a first frequency range of the first antennais covered in two switch stages, which are selectable by adjustment ofthe first capacitive element and the second capacitive element.

Example 30 includes the method of any one of examples 26 to 29,including or excluding optional features. In this example, a firstfrequency range of the first antenna is between 699 MHz to 960 MHz.

Example 31 includes the method of any one of examples 26 to 30,including or excluding optional features. In this example, the secondantenna includes: a first element configured to resonate at a frequencyrange between 1710 MHz and 2690 MHz; and a second element configured toresonate at a frequency range between 3400 and 3800 MHz.

Example 32 includes the method of any one of examples 26 to 31,including or excluding optional features. In this example, the secondantenna includes: a first element configured to resonate at a frequencyrange between 1710 MHz to 2690 MHz; a second element configured toresonate at a frequency range between 3400 and 3800 MHz; and a thirdelement configured to resonate at a frequency range between 5150 and5850 MHz. Optionally, the first element and second element are coupledto an indirect feed, and the third element is fed by the second element.

Some embodiments may be implemented in one or a combination of hardware,firmware, and software. Some embodiments may also be implemented asinstructions stored on the tangible non-transitory machine-readablemedium, which may be read and executed by a computing platform toperform the operations described. In addition, a machine-readable mediummay include any mechanism for storing or transmitting information in aform readable by a machine, e.g., a computer. For example, amachine-readable medium may include read only memory (ROM); randomaccess memory (RAM); magnetic disk storage media; optical storage media;flash memory devices; or electrical, optical, acoustical or other formof propagated signals, e.g., carrier waves, infrared signals, digitalsignals, or the interfaces that transmit and/or receive signals, amongothers.

An embodiment is an implementation or example. Reference in thespecification to “an embodiment,” “one embodiment,” “some embodiments,”“various embodiments,” or “other embodiments” means that a particularfeature, structure, or characteristic described in connection with theembodiments is included in at least some embodiments, but notnecessarily all embodiments, of the present techniques. The variousappearances of “an embodiment,” “one embodiment,” or “some embodiments”are not necessarily all referring to the same embodiments.

Not all components, features, structures, characteristics, etc.described and illustrated herein need be included in a particularembodiment or embodiments. If the specification states a component,feature, structure, or characteristic “may”, “might”, “can” or “could”be included, for example, that particular component, feature, structure,or characteristic is not required to be included. If the specificationor claim refers to “a” or “an” element, that does not mean there is onlyone of the element. If the specification or claims refer to “anadditional” element, that does not preclude there being more than one ofthe additional element.

It is to be noted that, although some embodiments have been described inreference to particular implementations, other implementations arepossible according to some embodiments. Additionally, the arrangementand/or order of circuit elements or other features illustrated in thedrawings and/or described herein need not be arranged in the particularway illustrated and described. Many other arrangements are possibleaccording to some embodiments.

In each system shown in a figure, the elements in some cases may eachhave a same reference number or a different reference number to suggestthat the elements represented could be different and/or similar.However, an element may be flexible enough to have differentimplementations and work with some or all of the systems shown ordescribed herein. The various elements shown in the figures may be thesame or different. Which one is referred to as a first element and whichis called a second element is arbitrary.

It is to be understood that specifics in the aforementioned examples maybe used anywhere in one or more embodiments. For instance, all optionalfeatures of the computing device described above may also be implementedwith respect to either of the methods or the computer-readable mediumdescribed herein. Furthermore, although flow diagrams and/or statediagrams may have been used herein to describe embodiments, thetechniques are not limited to those diagrams or to correspondingdescriptions herein. For example, flow need not move through eachillustrated box or state or in exactly the same order as illustrated anddescribed herein.

The present techniques are not restricted to the particular detailslisted herein. Indeed, those skilled in the art having the benefit ofthis disclosure will appreciate that many other variations from theforegoing description and drawings may be made within the scope of thepresent techniques. Accordingly, it is the following claims includingany amendments thereto that define the scope of the present techniques.

What is claimed is:
 1. An electronic device with a broadband antennasystem comprising: a first antenna to operate at a first frequency rangeand coupled to a first transceiver via a first signal path comprising afirst indirect feed; a second antenna to operate at a second frequencyrange and coupled to a second transceiver via a second signal pathcomprising a second indirect feed, wherein the first frequency range islower than the second frequency range; and a third antenna to operate atthe second frequency range and coupled to a third transceiver through athird signal path comprising a third indirect feed; wherein the firstantenna is coupled to the second antenna and the third antenna bycapacitive coupling elements.
 2. The electronic device of claim 1,wherein the first antenna is to operate in a dual loop mode through thesecond antenna and the third antenna.
 3. The electronic device of claim1, wherein the capacitive coupling elements are tunable to adjust aresonant frequency of the first antenna.
 4. The electronic device ofclaim 1, wherein the first frequency range of the first antenna iscovered in two switch stages, which are selectable by adjustment of thecapacitive coupling elements.
 5. The electronic device of claim 1,wherein the first frequency range of the first antenna is between 699MHz and 960 MHz.
 6. The electronic device of claim 1, wherein the secondantenna comprises a single resonant element configured to resonate at afrequency range between 1710 MHz and 2690 MHz.
 7. The electronic deviceof claim 1, wherein the second antenna comprises: a first elementconfigured to resonate at a frequency range between 1710 MHz and 2690MHz; and a second element configured to resonate at a frequency rangebetween 3400 and 3800 MHz.
 8. The electronic device of claim 1, whereinthe second antenna comprises: a first element configured to resonate ata frequency range between 1710 MHz to 2690 MHz; a second elementconfigured to resonate at a frequency range between 3400 and 3800 MHz;and a third element configured to resonate at a frequency range between5150 and 5850 MHz.
 9. The electronic device of claim 8, wherein thefirst element and second elements are coupled to an indirect feed, andthe third element is fed by the second element.
 10. The electronicdevice of claim 1, wherein: the first antenna comprises a straight metalbar disposed along a first surface of the electronic device; the secondantenna comprises a first curved metal bar disposed around a firstcorner of the electronic device adjacent to the first surface; and thethird antenna comprises a second curved metal bar disposed around asecond corner of the electronic device adjacent to the first surface.11. A method of operating an electronic device with a broadband antennasystem comprising: feeding a first antenna at a first frequency rangevia a first signal path comprising a first indirect feed; feeding asecond antenna at a second frequency range via a second signal pathcomprising a second indirect feed, wherein the first frequency range islower than the second frequency range; and feeding a third antenna atthe second frequency range via a third signal path comprising a thirdindirect feed; wherein the first antenna is coupled to the secondantenna and the third antenna by capacitive coupling elements.
 12. Themethod of claim 11, wherein the first antenna operates in a dual loopmode through the second antenna and the third antenna.
 13. The method ofclaim 11, comprising adjusting a capacitance of the capacitive couplingelements to adjust a resonant frequency of the first antenna.
 14. Themethod of claim 11, comprising: selecting a first switch stage of thefirst antenna by selecting a first capacitance level of the capacitivecoupling elements; and selecting a second switch stage of the firstantenna by selecting a second capacitance level of the capacitivecoupling elements.
 15. The method of claim 11, wherein the firstfrequency range of the first antenna is between 699 MHz to 960 MHz. 16.The method of claim 11, wherein the second antenna comprises a singleresonant element configured to resonate at a frequency range between1710 MHz and 2690 MHz.
 17. The method of claim 11, wherein the secondantenna comprises: a first element configured to resonate at a frequencyrange between 1710 MHz and 2690 MHz; and a second element configured toresonate at a frequency range between 3400 and 3800 MHz.
 18. The methodof claim 11, wherein the second antenna comprises: a first elementconfigured to resonate at a frequency range between 1710 MHz to 2690MHz; a second element configured to resonate at a frequency rangebetween 3400 and 3800 MHz; and a third element configured to resonate ata frequency range between 5150 and 5850 MHz.
 19. The method of claim 18,comprising feeding the first element and second element via the secondindirect feed, and feeding the third element via the second element. 20.The method of claim 11, wherein: the first antenna comprises a straightmetal bar disposed along a first surface of the electronic device; thesecond antenna comprises a first curved metal bar disposed around afirst corner of the electronic device adjacent to the first surface; andthe third antenna comprises a second curved metal bar disposed around asecond corner of the electronic device adjacent to the first surface.21. An electronic device with a broadband antenna system comprising: afirst antenna comprising a straight metal bar disposed along a firstsurface of the electronic device and coupled to a first transceiver viaa first indirect feed; a second antenna comprising a first curved metalbar disposed around a first corner of the electronic device adjacent tothe first surface and coupled to a second transceiver via a secondindirect feed; and a third antenna comprising a second curved metal bardisposed around a second corner of the electronic device adjacent to thefirst surface and coupled to a third transceiver via a third indirectfeed.
 22. The electronic device of claim 21, wherein the first antennais to operate at a first frequency range, and the second antenna andthird antenna are to operate at a second frequency range higher than thefirst frequency range.
 23. The electronic device of claim 21, whereinthe first antenna operates in a dual loop mode through the secondantenna and the third antenna.
 24. The electronic device of claim 21,comprising: a first capacitive element coupling the straight metal barof the first antenna to the first curved metal bar of the secondantenna; and a second capacitive element coupling the straight metal barof the first antenna to the second curved metal bar of the thirdantenna;
 25. The electronic device of claim 24, wherein the firstcapacitive element and the second capacitive element are tunable toadjust a resonant frequency of the first antenna.